Despite known advantages of LEDs in comparison with other light sources as regards lifetime, reliability, robustness and efficiency, LED-based light sources have not yet replaced traditional light sources in all fields of application. This is not least due to the thermal behavior of the light-emitting diodes: when the maximum permitted temperature is exceeded, i.e. the so-called junction temperature which typically lies in the range of 120-160° C., the LEDs are destroyed. The lifetime of LEDs also depends strongly on the operating temperature. Additional measures are therefore required in order to manage the thermal behavior of LED systems. Furthermore, LEDs cannot in general be operated readily from the mains, but require special drivers or current regulators since LEDs per se are current-controlled elements. Known LED radiators furthermore differ greatly from the shape of a conventional light bulb, which is detrimental to customer acceptance. For example an LED lamp with an E27 cap for operation at 230 V is known, in which the LEDs are mounted exposed without a cover on a flat support.
Owing to these problems, light bulbs have not yet been fully replaced by LED retrofits.